It's from a deck of cards my buddy put together that's loaded with
52 cool “dry-fire” gun drills you can do at home.
Since most attacks happen in low-light conditions, this exercise is a very realistic way to see how you do.
I used my SIRT training gun for this but you can just use your unloaded (safe!) personal weapon (or even a shotgun or whatever) to give this a try…
Dry-Fire Gun Training Exercise For Low-Light Home Defense
If you can't see the image, the card says this…
Have a training partner place cans or post-it notes around a room. Turn off the lights. Enter the room with your flashlight and weapon ready. Find and engage each target.
What I liked about this dry-fire drill was that it also helped me to consider cover and concealment while seeking out the cans my partner set up around my home.
It's one thing to look around and see those spots… but it's another matter to understand how they change in relation to you moving through your home and seeing where you're vulnerable from different angles when you don't know where the threat is.
I also suggest timing your target identification with a training partner to add some sense of urgency and “stress” to the scenario.